Fuse construction



April 14, 1942. s. l. LINDELL EI'AL FUSE CONSTRUCTION Filed Dec. 28, 1939 3 Sheets-Sheet l T i L RED GLASS S. l. LINDELL EI'AL FUSE CONSTRUCTION April 14, 1942.

P 1942- s. l. LINDELL ETAL FUSE CONSTRUCTION Filed Dec. 28, 1939 3 Sheets-Sheet 3 mmYSW QMQ Inventormm' I Lmdezz may flag/2 Q 35% Qmk Patented Apr. 14, 1942 UNITED STATES PATENT OFFICE FUSE CONSTRUCTION Sigurd I. Lindell and Anthony Van Ryan, Chicago, 111., assignors to Schweitzer & Conrad, Inc., Chicago, 111., a corporation of Delaware Application December 28, 1939, Serial No. 311,336

Claims. (Cl. 200117) This invention relates, generally, to circuit interrupting apparatus and it has particular relation to fuse devices for out-of-doors mounting and connection in low voltage or secondary distribution circuits.

' The object of the invention, generally stated, is to provide a fuse device for out-of-doors mounting and connection in secondary circuits that shall be simple and efficient in operation, that can be readily and economically manufactured and installed, and that can be re-fused with a minimum of danger to the lineman.

An object of the invention is to provide for installing a fuse link in a fuse tube that is connected in a circuit in such a manner that the circuit is not completed merely as a result of the installation of the fuse link in operative position, thereby not requiring that the fuse tube be disconnected from the circuit prior to installation of the fuse link.

Another object of the invention is to provide for connecting the fuse link into the circuit after it has been installed in operative position.

A further object of the invention is to provide for first closing one end of the fuse tube and thereafter connecting the fuse link into the circuit.

Still another object of the invention is to pro vide for holding the fuse link in operative position before the end of the fuse tube is closed and the fuse link is connected into the circuit.-

An object of the invention is to fully and adequately protect a fuse tube having arc extinguishing properties from the effects of the weather.

Another object of the invention is to provide for indicating, in a new and improved manner, that the fuse link in a fuse tube has blown.

Still another object of the invention is to provide an indication that can be readily detected at night that the fuse link has blown.

A further object of the invention is to provide for utilizing the relatively great force that can be exerted by a coil compression spring around a stationarily mounted fuse tube for holding a fuse link in operative position in the fuse tube and separating its terminals when it blows.

A still further object of the invention is to provide for operatively interconnecting a spring biased sleeve slidably mounted on a fuse tube and restrained by a fuse link and an indicator which moves to indicating position when the fuse link blows.

Other objects of the invention will, in part, be obvious and in part appear hereinafter.

The invention, accordingly, is disclosed in the embodiments thereof shown in the accompanying drawings, and it comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the application of which will be indicated in the appended claims.

For a more complete understanding of the nature and scope of the invention, reference may be had to the following detailed description taken in connection with the accompanying drawings, in which:

Figure 1 is a view, in side elevation, of one embodiment of the indicating secondary cutout;

Figure 2 is a longitudinal sectional View taken along the line 22 of Figure 1;

Figure 3 is a detail sectional view, taken along the line 3-3 of Figure 2, for the purpose of showing the cap and the insulating sleeve therein;

Figure 4 is a bottom plan view of the cutout shown in Figure 1;

Figure 5 is a sectional view of a modified form of cap construction;

Figure 6 is a view in side elevation of a modified form of the invention;

Figure 7 is a. longitudinal sectional view taken along the line 1-1 of Figure 6; and

Figure 8 is a longitudinal sectional view of still another embodiment of the invention.

Referring now particularly to Figures 1 and 2 of the drawings, it will be observed that reference characters l0 and II designate line conductors. These line conductors may form part of the circuit connecting the low voltage side of a distribution transformer to a load circuit. For example, the conductor l0 may be connected to one terminal of the secondary winding of the distribution transformer and the conductor ll may be connected to the load circuit which is intended to be energized at a standard voltage, i. e., 220 or volts. The conductors I0 and H are interconnected through a secondary cutout which serves to open the circuit therebetween on the occurrence of a fault on the secondary distribution circuit.

It will be observed that the conductors Ill and I I are connected by suitable clamp means I2 and I3 to arms I4 and I5 extending respectively from upper and lower fuse tube terminals, shown generally at I6 and H. The arms l4 and I5 are integrally formed with the terminals l6 and I7 which are preferably formed by castings of suitable high conductivity metal such as bronze.

Referring now particularly to Figure 2 of the drawings, it will benoted that the terminals [6 and H are mounted on a fuse tube 2| having a liner 22 within the bore 23 of which a fuse link, shown generally at 24, is adapted to be placed in operative position. The fuse tube 2| is preferably formed of a phenolic condensation product while the liner 22 is preferably formed of a material, such as fiber, from the bore 23 of which can be readily expelled therefrom. The termi nals and 26 are interconnected by a fusible element 28, preferably formed of silver wire, and a strain element 29, preferably formed of high strength wire such as nickel-chromium alloy wire. A flexible lead 30 is connected to the terminal 26 and extends out of the tube or sleeve 21 and also out of the bore 23 a sufllcient distance as to permit its being disposed around a stud 3|, extending from the lower fuse terminal l1, and being securely clamped in position by means of a thumb nut 32. The terminal 25 of the fuse link 24 is threaded into a flanged head 36 underneath which a washer 31 is provided, the diameter of which is substantially greater than the diameter of the bore 23 so as to prevent the fuse link 24 from being drawn through the fuse tube 2| beyond the position illustrated. It will be understood that the flanged head 36 could be so formed as to have a diameter as great as the diameter of the washer 91, thereby making the use of it unnecessary. Further, it will be understood that the terminal 25 could be formed integrally with a flanged head having this diameter. However, in order to adapt the fuse link 24 for mounting in various types of cutouts, the construction shown is preferred. Y

. The flanged upper end of the fuse link 24 engages a metallic thimble 38 which is provided in order to prevent abrasion of the upper ends of the fuse tube 2| and the liner 22, and also to provide a solid seat against which the washer 31 and flanged head 36 can be securely clamped.

It will be understood that the fuse link 24 is placed in operative position within the fuse tube 2| by introducing the flexible lead 30 through the upper end and then pulling the fuse link or allowing it to drop to the position shown in Figure 2 of the drawings. It has been customary practice in the past, when the fuse link has been thus positioned within the fuse tube, to have the upper end or flanged head of the fuse link in contact engagement with the upper fuse tube terminal. Then, as soon as the flexible lead is connected to the lower fuse tube terminal, the circuit is completed through the fuse link. If the fault still exists on the circuit, then the fuse link is immediately blown. If the lineman has his hands in the vicinity of the lower end of the fuse tube for the purpose of connecting the flexible lead to the lower fuse tube terminal, it is quite likely that the products of the arc expelled from the fuse tube may severely burn them.

In order to overcome this difficulty, the upper fuse tube terminal I6 is provided with a threaded portion 39 which, instead of being positioned at the extreme upper end of the fuse tube 2| where it would be engaged by the flanged upper end of the fuse link 24 as soon as it is placed in operative position, it is placed, as indicated at 40, a considerable distance from the upper end so that,

when the fuse link 24 is placed in operative position, its flanged upper end is not in contact engagement with the upper fuse tube terminal IS. The flexible lead 36 can then be safely clamped in position around the stud 3| by the thumb nut 32 without any danger to the lineman.

After the fuse link 24 has been secured in operative position, a metal cap 4|, interiorly threaded at its lower end 42 is placed over the upper end of the fuse tube 2|. On turning the cap 4| the threaded lower end 42 is threaded upon the threaded portion 39 of the upper fuse tube terminal l6, thereby first closing the upper end of the fuse tube 2 I.

The circuit through the fuse link 24 is not completed until the cap 4| has been screwed downwardly sufficiently far so that its underside engages the terminal 25 and flanged head 36 of the fuse link 24. If now the fuse link 24 immediately blows, it will be understood that the lineman will be out of danger since his hands should be entirely away from the lower end of the fuse tube 2|. Moreover, it will be understood that the fuse link 24 will operate under the same conditions that it would operate after havingbeen installed for some time and then a fault occurring on the circuit.

With a view to further preventing interconnection between the flanged head of the fuse link 24 and the upper fuse tube terminal l6 until the cap 4| is screwed into position, an insulating sleeve 43 is provided inside of the cap 4| between the threaded lower end portion 42 and the underside of the top. The sleeve 43 is split, as shown more clearly in Figure 3 of the drawings, in order to facilitate placing it in position and to hold the same in position inside of the cap 4|.

In Figure 5 of the drawings it will be observed that the cap 4| is provided with an outer sleeve 44 of insulation which fits tightly around the lower portion of the same and may be secured there to by any suitable means, for example by cement. The upper edge of the sleeve 44 bears against a shoulder of the cap 4| while the lower edge of the cap 4| bears against a shoulder formed by the thicker lower portion 45 of the sleeve 44. This construction, because of the sleeve 44, prevents accidental contact engagement by the cap 4| with both the upper fuse terminal l6 and the metallic parts at the upper end of the fuse link 24. The upper fuse tube terminal I6 is securely held in position on the fuse tube 2| and spaced from the upper end by means of pins extending transversely through the terminal l6 and the fuse tube 2 I, one of the pins being shown by the broken lines at 46. It will be understood that two pins are provided, one on each side of the liner 22.

It is desirable that the fuse tube 2| be entirely protected from the effects of the weather. The upper fuse tube terminal l6 and the cap 4| serve to effectively cover the upper end portion of the fuse tube 2|. With a view to accomplishing this purpose the upper fuse terminal I6 is provided with a depending flange 41 within which the reduced upper end portion 48 of an insulating sleeve 49 extends. The lower reduced portion 50 of the sleeve 49 is spaced slightly from the lower fuse tube terminal ll, as illustrated. Between the end portions 48 and 5|) of the sleeve 49 and the adjacent surfaces of the upper and lower fuse terminals I6 and H, respectively, there is positioned sealing means in the form of washers or gaskets 5| and 52 of leather or other suitable material so that the entrance of moisture is prevented and at the same time there is no likelihood of injury to the sleeve 49 which is preferably fclirmed of frangible material such as porcelain or g ass.

It will be observed that the sleeve 49 is provided with a groove 53 intermediate of its ends for receiving a band 54 that is arranged to be clamped by bolts 55 to a support bracket 55. The

support bracket 55 can be mounted on a cross arm or other suitable support as will be readily understood. The clamping and supporting structure provided by the band 54 and the bracket 55 are preferably of the type shown in the copending application of Triplett & Lindell, Serial No. 302,- 986, filed November 6, 1939.

Again referring to Figure 2 of the drawings, it will be observed that the lower fuse tube terminal includes a sleeve portion 51 that surrounds the fuse tube 2| and is spaced from the lower end thereof. Pins 51, extending transversely through the sleeve portion 5'! and the fuse tube 2| on opposite sides of the liner 22 serve to hold the lower fuse tube terminal I! securely in position.

It is desirable to hold the fuse link 24 in operative position while the cap 4| is being screwed into place, to quickly separate the fuse link terminals 25 and 25 when the fuse link blows, and to provide an indication that the fuse link has blown which can be readily observed, particularly at night. With a view to accomplishing these ends, a lever 58, underneath which the flexible lead 30 is passed is rotatably mounted on a shaft 58' that extends through the depending walls of a housing 59 which completely encloses the lower end of the fuse tube 2| and, as shown, projects slightly below it. The lever 58 is biased by a coil spring 58 that is positioned around the hub of the lever 58 with one end 5| bearing against'the inner surface of the houslng59 and the other end 52 engaging the lever 58. When the fuse link 24 blows,.the lever 58 is rotated under the influence of the coil spring 88 and serves to withdraw the flexible lead 85 and to separate the terminals 25 and 25, thereby elongating the arc therebetween for assisting in extinguishing it.

When the fuse link 24 is placed in operative position in the fuse tube 2| with the flexible lead 90 passing underneath the lever 58 and clamped by' the thumb nut 32, the fuse link is held securely in this position because of the biasing action of the spring 58 and, therefore, there is no likelihood of the fuse link 24 popping out of the upper end of the fuse tube 2| and accidentally coming into contact engagement with the metallic cap 4| before it is securely screwed into position.

As shown more clearly in Figure 4 of the drawings, the underside of the lever 58 is grooved, as

1 indicated at 53, in order to securely hold the flexible lead 35 therein. The rear end 54 of the lever 58 is arranged to limit the movement thereof on engagement with the base of a slot 55 in the depending housing 59.

Pins 55 projecting from the housing 59 below and on opposite sides of the stud 3| serve to further hold the flexible lead 30 in proper position, it being understood that the portions of .the flexible lead on opposite sides of the stud 3| are positioned between the pins 55.

The indicating feature is provided in part by an arm 51 that is integrally formed with the hub of the lever 58 and, of course, moves therewith. The outer end 58 of the arm 51 is turned inwardly for carrying a reflecting button 59 having a plurality of angularly related facets. The reflector button 59 is preferably formed of distfnctively colored transparent material such as glass or plastic colored red and is of the general type of reflector buttons that are now widely used as danger signalson automobiles, highway signs, etc. The reflector button 69 is carried by a support member 18 which includes a stud 1| that projects through the end 58 of the arm 51 and has a clamp nut 12 threaded thereon.

When the fuse link 24 blows, the lever 58 is no longer restrained, as previously described, and it rotates under the influence of the spring 5|! until the rear end 64 engages the base of the slot 55 in the housing 59. The arm 51 and the reflector button 59, which are held hidden inside of the housing 59 as long as the fuse link 24 remains intact, move with the lever 58 under the influence of the spring 50 to the position shown by the broken lines in Figure 2. It will be observed that the reflector button 59 is substantially in alignment with the longitudinal axis of the arm 5! and that it is clearly visible from a position directly underneath the fuse tube 2|. When it is recalled that the devic is intended to be mounted overhead, it will be readily understood that this construction materially facilitates the discovery by a lineman of a blown fuse link. This is true particularly at night when a flashlight or spotlight playing on the underside of the device will promptly indicate whether or not the fuse link 24 has blown.

In Figures 6 and '7 of the drawings there is shown an embodiment of the invention that is generally similar to the embodiment shown in Figures 1, 2, 3 and 4 and described hereinbefore.

In the construction shown in Figures 6 and 7, the upper fuse tube terminal I5 has been positioned on the fuse tube 2| so that in place of having the arms l4 and I5 to which the line conductors l0 and II are connected in the same plane, they are positioned in planes at right angles to each other. The cutout shown in Figures 6 and '7 of the drawings is intended to be supported entirely from the line conductors l0 and II, the supporting clamp and the additional insulating sleeve 49 being omitted.

In Figure 8 of the drawings another embodiment of the invention is illustrated. As there shown a fuse tube 14 is provided having a liner 15 for receiving through the upper end a fuse link 24 in a manner described hereinbefore. At its upper end the fuse tube 14 is provided with an upper fuse tube terminal, shown generally at 15, having a threaded portion 11 spaced from the upper end of the fuse tube 10 for the purpose which has been described in detail above. A metal cap 18 is arranged to be threaded onto the threaded portion 17 of the upper fuse tub terminal 16 for the purpose of closing the upper end of the fuse tube 14 and thereafter to interconnect the terminal 16 and the flanged upper end of the fuse link 24. The terminal 15 is provided with a threaded extension 19 into which a clamp stud can be screwed. The clamp stud 80 and the clamp nut thereon are provided for connecting the terminal 75 to the line conductor III. A pin 8| extending transversely through the main body portion of the terminal 15 and the fuse tub 14 serves to hold the terminal 16 securely in position on the fuse tube 14.

At its lower end the fuse tube 14 is provided with a lower fuse tube terminal, hown generally at 83, which includes a sleeve-like portion 84 surrounding the fuse tube 74 and secured thereto by a transverse pin 85. The terminal 83 also includes a downwardly extending housing 85 which, in addition to protecting the mechanism at the lower end of the fuse tube 14 from the weather also serves to obscure the indicator button 69 when the fuse link 24 is intact. The housing 86 is provided with a rearwardly extending portion 81 for receiving a doubl ended clamp stud 88, the upper portion serving to connect the terminal 83 to the line conductor l and the lower portion being adapted to receive and clamp and flexible lead 30 of the fuse link 24. With a view to holding the fuse link 24 in operative position while the metallic cap 18 is being screwed into place, to separate the terminals of the fuse link 24 when it blows, and to provide an indication that the fuse link 24 has blown, a sleeve 9| is slidably mounted on the reduced lower end portion of the fuse tube 14 and is arranged to slide relative thereto. A coil compression spring 92 surrounds the reduced portion of the fuse tube 14 and reacts between a flange formed thereby and an inwardly extending flange of the sleeve 9| for biasing the latter downwardly. Integrally formed with the sleeve 9| is a boss 93 which has a portion that projects into a longitudinal slot 94 in the sleeve I4 and liner I5 which permits the flexible lead 30 to be brought out of the fuse tube 14 and over the boss 93 which is grooved slightly, as indicated at 95, in order to facilitate retaining the flexible lead 30. When the end of the flexible lead 391s clamped, as shown, the sleeve 9| will be held in the retracted P sition with the boss 93 substantially at the upper end of the slot 94.

The sleeve 9| i provided with teeth 96 which are arranged to engage transverse pins 91 carried by an arm 98 that is mounted for rotation on a shaft 99 carried by the housing 86. It will be observed that the indicator button 69 is mounted at the outer end of the arm 98. The teeth 95 and pins 91 provide, in effect, a rack and pinion connection between the sleeve 9| and the arm 98 whereby they are operatively interconnected so that movement of the sleeve 9| downwardly is accompanied by a downward swinging of the arm 98.

As long as the fuse link 24 remains intact, the sleeve 9| is held in the retracted position, together with the arm 98. The reflector button 69 is then effectively hidden from view. When the fuse link 24 blows, the sleeve 9| is moved downwardly under the biasing force of the coil compression spring 92 and it carries with it the flexible lead 30, thereby serving to separate the terminals of the fuse link 24, as will be readily understood. Because of the rack and pinion connection between the sleeve 9| and the arm 98, the latter is rotated downwardly and carries with it the indicator button 69 which, by its position underneath the fuse tube 14 shows to the lineman that the fuse link therein has blown and should be replaced.

In all of the embodiments of the invention disclosed herein, it will be apparent that it is unnecessary to disturb the connections to the line conductors l0 and II when the cutout is refused. A new fuse link can be safely installed in operative position by the lineman without completing the connection between the line conductors l0 and II. It is only when the metallic cap 4| or 18 is screwed into position that the.circuit through the fuse link is completed. When this occurs, the cutout is completely in operative condition and can most effectively operate to interrupt the circuit.

Since certain further changes may be made in the foregoing constructions and different embodiments of the invention can be made without departing from the scope thereof, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed as new is:

1. In a fuse device adapted to remain connected in a circuit during refusing, in combination, a fuse tube for receiving a fuse link, a terminal adjacent one end of said fuse tube, meanspermanently connecting said terminal to a normally energized line conductor, said fuse link when placed in operative position in said fuse tube being unconnected to said terminal whereby said fuse link is not energized, and means for interconnecting said fuse link and said terminal after the former has been positioned in said fuse tube.

2. In a fuse device adapted to remain connected in a circuit during refusing", in combination, a fuse tube for receiving a fuse link, a terminal adjacent one end of said fuse tube, means permanently connecting said terminal to a normally energized line conductor, said fuse link when placed in operative position in said fuse tube being unconnected to said terminal whereby said fuse link is not energized, and metallic cap means adapted first to close said one end of said fuse tube and next to interconnect said fuse link and said terminal when operated to a predetermined position so as to energize said fuse link.

3. In a fuse device adapted to remain connected in a circuit during refusing, in combination, a fuse tube for receiving a fuse link, a terminal adjacent one end of said fuse Lube, means permanently connecting said terminal to a normally energized line conductor, said fuse link when placed in operative position in said fuse tube being unconnected to said terminal whereby said fuse link is not energized, metallic cap means adapted to close said one end of said fuse tube and to interconnect said fuse link and said terminal when operated to a predetermined position so as to energize said fuse link, and insulating means within said cap means adapted to prevent contact engagement between said cap means and said fuse link while the former is being placed in position on said terminal.

4. In a fuse device adapted to remain connected in a circuit during refusing, in combination, a fuse tube for receiving a fuse link, a terminal adjacent one end of said fuse tube, means permanently connecting said terminal to a normally energized line conductor, said fuse link when placed in operative position in said fuse tube being unconnected to said terminal whereby said fuse link is not energized, metallic cap means adapted to close said one end of said fuse tube and to interconnect said fuse link and said terminal when operated to a predetermined position so as to energize said fuse link, and insulating means surrounding said cap for preventing accidental contact engagement with both said terminal and said fuse link in placing said cap in operative position.

5. In a fuse device adapted to remain connected in a circuit during refusing, in combination, a fuse tube for receiving a fuse link, a terminal adjacent one end of said fuse tube, means permanently connecting said terminal to a normally energized line conductor, said fuse link when placed in operative position in said fuse tube being unconnected to said terminal whereby said fuse link is not energized, metallic cap means adapted to close said one end of said fuse tube and to interconnect said fuse link and said terminal when operated to a predetermined position so as to energize said f uselink, insulating means surrounding said cap for preventing accidental contact engagement with both said terminal and said fuse link in placing said cap in operative position, and insulating means within said cap means adapted to prevent contact engagement between said cap means and said fuse link while the former is being placed in position on said terminal.

6. In a fuse device adapted to remain connectcd in a circuit during refusing, in combination, a fuse tube for receiving through one end a fuse link having as one terminal a flanged head larger than the bore of said fuse tube, a line terminal surrounding said fuse tube and spaced from said one end, means permanently connecting said terminal to a normally energized line conductor, said flanged head abutting said one end of said fuse tube and being unconnected to said line terminal when said fuse link is in operative position in said fuse tube whereby said fuse link is not energized, and a metallic cap adapted to cooperate with said line terminal first to close said one end of said fuse tube and subsequently to interconnect said flanged head and said line terminal so as to energize said fuse link.

7. In a fuse device, in combination, a line terminal having a tubular exteriorly threaded portion, a fuse tube of insulating material within and projecting at one end a substantial distance beyond said line terminal for receiving through said one end a fuse link having as one terminal a flanged head larger than the bore of said fuse tube, said flanged head of said fuse link in operative position abutting said one end of said fuse tube and being insulated from said line terminal thereat, and a metallic cap having an interiorly threaded portion for engaging said threaded portion of said line terminal for first closing said one end of said fuse tube and subsequently when further screwed onto said line terminal interconnecting the same with said flanged head.

8. In a fuse device, in combination, a line terminal having a tubular exteriorly threaded portion, a fuse tube of insulating material within and projecting at one end a substantial distance beyond said line terminal for receiving through said one end a fuse link having as one terminal a flanged head larger than the bore of said fuse tube, said flanged head of said fuse link in operative position abutting said one end of said fuse tube and being insulated from said line terminal thereat, a metallic cap having an interiorly threaded portion for engaging said threaded portion of said line terminal for first closing said one end of said fuse tube and subsequently when further screwed onto said line terminal interconnecting the same with said flanged head, and a sleeve of insulation within said cap adapted to prevent contact engagement between it and said flanged head while the cap is being placed in position on said terminal.

9. In a fuse device adapted to remain connected in a circuit during refusing, in combination, a fuse tube for receiving a fuse link, a terminal adjacent one end of said fuse tube, means permanently connecting said terminal to a normally energized line conductor, said fuse link when placed in operative position in said fuse tube being unconnected to said terminal whereby said fuse link is not energized, means for interconnecting said fuse link and said terminal after the former has been positioned in said fuse tube so as to energize said fuse link, and means at the other end of said fuse tube disposed to be operatively connected to said fuse link for tensioning the same to hold it in operative position during installation of said interconnecting means.

10. In a fuse device adapted to remain connected in a circuit during refusing, in combination, a fuse tube for receiving through one end a fuse link having as one-terminal a flanged head larger than the bore of said fuse tube, a line terminal surrounding said fuse tube and spaced from said one end, means permanently connecting said terminal to a normally energized line conductor, said flanged head abutting said one end of said fuse tube and being unconnected to said line terminal when said fuse link is in operative position in said fuse tube whereby said fuse link is not energized, a metallic cap adapted to cooperate with said line terminal first to close said one end of said fuse tube and subsequently to interconnect said flanged head and said line terminal so as to energize said fuse link, a lever pivoted adjacent the other end of said fuse tube and disposed to be operatively connected to said fuse link, and spring means biasing said lever for holding said flanged head in said abutting relation while said metallic cap is being placed in position.

11. In a fuse device, in combination, a line terminal having a tubular exteriorly threaded portion, a fuse tube of insulating material within and projecting at one end a substantial distance beyond said line terminal for receiving through said one end a fuse link having as one terminal a flanged head larger than the bore of said fuse tube and as the other terminal a flexible lead, said flanged head of said fuse link in operative position abutting said one end of said fuse tube and being insulated from said line terminal thereat with said flexible lead extending out of the other end of said fuse tube, a metallic cap having an interiorly threaded portion for engaging said threaded portion of said line terminal for first closing said one end of said fuse tube and subsequently when further screwed onto said line terminal interconnecting the same with said flanged head, movable means at the other end of said fuse tube operatively engaging said flex ible lead, and spring means biasing said movable means for tensioning said fuse link and holding said flanged head in said abutting relation while said metallic cap is being screwed into said connecting position.

12. In a fuse device, in combination, a line terminal having a tubular exteriorly threaded portion, a fuse tube of insulating material within and projecting at one end a substantial distance beyond said line terminal for receiving through said one end a fuse link having as one terminal a flanged head larger than the bore of said fuse tube and as the other terminal a flexible lead, said flanged head of said fuse link in operative position abutting said one end of said fuse tube and being insulated from said line terminal thereat with said flexible lead extending out of the other end of said fuse tube, a metallic cap having an interiorly threaded portion for engaging said threaded portion of said line terminal for first closing said one end of said fuse tube and subsequently when further screwed onto said line terminal interconnecting the same with said flanged head, a lever pivoted adjacent the other end of said fuse tube and operatively engaging said flexible lead, and spring means biasing said lever for tensioning said fuse link and holding said flanged head in said abutting relation while said metallic cap is being screwed into said connecting position.

13. In a fuse device for interconnecting a pair of line wires and adapted to remain connected thereto during refusing, in combination, a fuse tube for receiving a fuse link}, terminals carried by'said fuse tube adjacent its ends and adapted to have said line wires permanently attached thereto, said fuse link when placed in operative position in said fuse tube being connected to one of said terminals and adjacent but unconnected to the other terminal whereby said fuse link is not energized, and means for interconnecting said fuse link and said other terminal whereby said fuse link can be placed in operative position and connected for energization between said terminals without danger to the lineman and without disconnecting said line wires from said terminals.

14. In a fuse device for interconnecting a pair of line wires and adapted to remain connected thereto during refusing, in combination, a fuse tube for receiving a fuse link, terminals carried by said fuse tube adjacent its ends and adapted to have said line wires permanently attached thereto, said fuse link when placed in operative position in said fuse tube being connected to one of said terminals and adjacent but unconnected to the other terminal whereby said fuse link is not energized, and metallic cap means adapted to close the end of said fuse tube adjacent to which said other terminal is connected and to interconnect said fuse link and said other terminal for energizing the former only when operated to a predetermined position after closing said end of said fuse tube.

15. In a fuse device for interconnecting a pair of line wires and adapted to remain connected thereto during re-fusing, in combination, a fuse tube for receiving a fuse link, terminals carried by said fuse tube adjacent its ends and adapted to have said line wires permanently attached thereto, said fuse link when placed in operative position in said fuse tube being connected to one of said terminals and adjacent but unconnected to the other terminal whereby said fuse link is not energized, metallic cap means adapted to close the end of said fuse tube adjacent to which said other terminal is connected and to interconnect said fuse link and said other terminal for energizing the former only when operated to a predetermined position after closing said end of said fuse tube, movable means carried by said fuse tube and operatively engaging said fuse link, and spring means biasing said movable means for tensioning said fuse link and holding the same in operative position while said metallic cap is being moved to said predetermined position.

16. In a fuse device, in combination, a fuse tube adapted to receive therein a fuse link having a flexible lead extending out of one end thereof, a longitudinal slot in said fuse tube at said one end, a sleeve around said fuse tube at said one end and movable relative thereto, a projection from said sleeve extending into said slot under which said flexible lead is positioned, and spring means biasing said sleeve for said relative movement and restrained by said fuse link.

1'7. In a fuse device, in combination, a fuse tube adapted to receive a fuse link therein, a

sleeve surrounding said fuse tube and movable relatively thereto and restrained from such movement by said fuse link, spring means biasing said sleeve and tensioning said fuse link, an indicator arm mounted for rotation about an axis movable with respect to said sleeve, and\ means operatively interconnecting said indicator arm and said sleeve whereby relative movement between said fuse tube and sleeve on blowing of said fuse link causes movement of said indicator arm from non-indicating to indicating position. a

18. In a fuse device, in combination, a fuse tube adapted to receive a fuse link therein, a sleeve surrounding said fuse tube and movable relatively thereto and restrained from such movement by said fuse link, a coil compression spring surrounding said fuse tube for biasing said sleeve and tensioning said fuse link, an indicator arm mounted for rotation about an axis movable with respect to said sleeve, and pinion and rack means operatively interconnecting said indicator arm and said sleeve whereby relative movement between said ,fuse tube and sleeve on blowing of said fuse link causes movement of said indicator arm from non-indicating to indicating position.

19. In a fuse device, in combination, a line terminal having a tubular exteriorly threaded portion, a fuse tube of insulating material within and projecting at one end a substantial distance beyond said line terminal for receiving through said one end a fuse link having as one terminal a flanged head larger than the bore of said fuse tube and as the other terminal a flexible lead, said flanged head of said fuse link in operative position abutting said one end of said fuse tube and being insulated from said line terminal thereat with said flexible lead extending out of the other end of said fuse tube, a metallic cap having an interiorly threaded portion for engaging said threaded portion of said line terminal for first closing said one end of said fuse tube and subsequently when further screwed onto said line terminal interconnecting the same with said flanged head, a sleeve slidably mounted on the other end of said fuse tube and operatively engaging said flexible lead, and coil spring means surrounding said fuse tube and biasing said sleeve for tensioning said fuse link and holding said flanged head in said abutting relation while" said metallic cap is being screwed into said connecting'position.

20. In a fuse device adapted to remain connected in a circuit during re-fusing, in combination, a fuse tube for receiving a fuse link, a terminal adjacent one end of said fuse tube, means permanently connecting said terminal to a normally energized line conductor, said fuse link when placed in operative position in said fuse tube being unconnected to said terminal whereby said fuse link is not energized, metallic cap means adapted to close said one end of said fuse tube and to interconnect said fuse link and said terminal when operated to a predetermined position so as to energize said fuse link, and insulating means carried by said cap means for preventing accidental contact engagement between it and said fuse link while the former is being moved to operative position on said terminal.

SIGURD I. LINDELL. ANTHONY VAN RYAN. 

